Slowing Seawater Intrusion

To our knowledge, MRWPCA operates the world's largest water recycling facility designed for raw food crop irrigation

The primary source for water in Monterey County is from aquifers hundreds of feet below the ground. The reserve is diminishing as the number of farms, businesses and residences have increased. So much water has been removed, in fact, that intruding seawater has come within two miles of Salinas's wells.

In the mid 1970s, a group of community leaders began discussing the idea of recycling wastewater. This led to the extensive five-year Monterey Wastewater Reclamation for Agriculture Study that began in 1980. The final results of this research proved that recycled water is safe for the irrigation of crops that are consumed without cooking. Today, this definitive report is used as the standard in countries all over the world.

In 1992, MRWPCA and the Monterey County Water Resources Agency formed a partnership to build two projects: a water recycling facility at the Regional Treatment Plant; and a distribution system including 45 miles of pipeline and 22 supplemental wells. Its objective was to retard the advance of seawater intrusion by supplying irrigation water to nearly 12,000 acres of farmland in the northern Salinas Valley. This would significantly reduce the draw of water from the undergound aquifers. The $75 million projects were completed in 1997 after three years of construction.

The use of highly treated wastewater to irrigate landscaping has been practiced for years, yet for food crops, it is relatively new. The recycled water facility is capable of producing an average of 29.6 million gallons of recycled water per day. This is the equivalent of one foot of water over 91 acres of land.

In the future, MRWPCA plans to additionally supply recycled water to city parks, roadway landscape and golf courses.